So your body is comfortable, satisfied and nothing is pressing on you or rushing you in any way. Take paper and a pen, you will need to make the odd note.
Building a communication bridge is most important and it's my opinion the supermarket is without a doubt one of the best places to do it. Yes/No answers and lots of them surround you from the entry to the exit.
A few years ago while I was shopping I was walking along saying to myself " I need bread, bread, bread, I need bread' and over the top of my voice came "and butter" and thats when I realised I didn't need a list. And I had help. How many times have you come home, discovered you were out of something and it had popped up and said hello to you, or popped into your head while shopping? Lightbulbs, toilet paper, tampons and rubbish bags are the real kickers.
Your body knows what it needs. It will endeavour to self-medicate through food if you ‘get out of the way.’ Your subconscious knows and will ‘show’ you what to take home of the essential items such as cleaners or rubbish bags, or while passing rubbish bags you may for instance suddenly remember you were interested in the possibility of getting a worm farm. Note this sort of thing down too.
After a time you will learn to shop, unhurried and hear your body/guides or guidance letting you know what is really good for you.
Wandering in the supermarket while you listen to your body takes the pressure and the unpleasantness out of grocery shopping. You can go into a walking meditation as you do it and you could even think up a mantra for health and wellbeing for your trolley.
You could even discover how to use your body as a pendulum.